"Though it was the most efficient, Auschwitz was not necessarily the cruellest of the Nazi death camps. The first people to be gassed by the Third Reich were, as we have seen, German mental patients; they had been asphyxiated with pure carbon monoxide gas. This method was then exported to Eastern Europe, but using exhaust fumes, first in specially converted vans, then in static gas chambers equipped with large diesel engines. This was how people were killed at Sobibor, Treblinka and Belzec, the camps set up to implement the 'Action Reinhard' in the autumn of 1941. Compared with inhaling Zyklon B, which killed most victims within five to ten minutes, this was a slow way to die. Rudolf Hoess, the commandant of Auschwitz, regarded his own methods as 'humane' compared with those of his counterpart at the last of these camps, the notoriously sadistic Christian Wirth."